:root {
    --primary-color: #1a3a6c;
    --secondary-color: #2c5282;
    --sidebar-width: 250px;
    --header-height: 70px;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f5f7fa;
    overflow-x: hidden;
    background-image: url('https://images.unsplash.com/photo-1600880292089-90a7e086ee0c?ixlib=rb-4.0.3&auto=format&fit=crop&w=1920&q=80');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
}

/* 顶部导航栏 */
.navbar-admin {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    height: var(--header-height);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.5rem;
    color: white !important;
}

/* 侧边栏 */
.sidebar {
    width: var(--sidebar-width);
    height: calc(100vh - var(--header-height));
    position: fixed;
    top: var(--header-height);
    left: 0;
    background-color: rgba(255, 255, 255, 0.95);
    box-shadow: 2px 0 10px rgba(0, 0, 0, 0.05);
    z-index: 100;
    overflow-y: auto;
    transition: all 0.3s;
    backdrop-filter: blur(5px);
}

.sidebar-menu {
    list-style: none;
    padding: 0;
    margin: 20px 0;
}

.sidebar-menu li {
    padding: 0;
}

.sidebar-menu a {
    display: flex;
    align-items: center;
    padding: 12px 20px;
    color: #4a5568;
    text-decoration: none;
    transition: all 0.2s;
    border-left: 4px solid transparent;
}

.sidebar-menu a:hover,
.sidebar-menu a.active {
    background-color: rgba(26, 58, 108, 0.1);
    color: var(--primary-color);
    border-left-color: var(--primary-color);
}

.sidebar-menu i {
    margin-right: 10px;
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
}

/* 主内容区域 */
.main-content {
    margin-left: var(--sidebar-width);
    padding: 30px;
    min-height: calc(100vh - var(--header-height));
    transition: all 0.3s;
}

/* 响应式设计 */
@media (max-width: 992px) {
    .sidebar {
        transform: translateX(-100%);
    }

    .sidebar.active {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
    }

    .menu-toggle {
        display: block;
    }
}